Communications system providing photonic conversion and power detection and related methods

Abstract

A communications system may include an optical source configured to generate an optical carrier signal, a first electro-optic (EO) modulator coupled to the optical source and configured to modulate the optical carrier signal based upon a radio frequency (RF) input, and photonic mixers associated with different respective frequencies across a frequency spectrum and coupled to the optical source and the first EO modulator. The system may further include at least one first opto-electronic (OE) detector coupled to the photonic mixers, and an analog-to-digital converter (ADC) coupled to the at least one OE detector and configured to generate a digital output signal based upon receiving an RF signal via the RF input.

That which is claimed is: 
     
       1. A communications system comprising:
 an optical source configured to generate an optical carrier signal; 
 a first electro-optic (EO) modulator coupled to the optical source and configured to modulate the optical carrier signal based upon a radio frequency (RF) input; 
 a plurality of photonic mixers each associated with a different respective frequency from among a plurality of different frequencies across a frequency spectrum and coupled to the optical source and the first EO modulator; 
 at least one first opto-electronic (OE) detector coupled to the plurality of photonic mixers; and 
 a common analog-to-digital converter (ADC) coupled to the at least one OE detector and configured to generate a digital output signal based upon the plurality of different frequencies across the frequency spectrum. 
 
     
     
       2. The communications system of  claim 1  wherein each photonic mixer comprises:
 a first path coupled to the first EO modulator and comprising a first optical bandpass filter (BPF) and an optical power meter coupled to the first optical BPF; 
 a second path coupled to the optical source and comprising an optoelectronic oscillator (OEO) and a second optical BPF coupled to the OEO; and 
 an optical coupler coupled to the first and second paths. 
 
     
     
       3. The communications system of  claim 2  wherein the OEO further comprises:
 a second EO modulator coupled to the optical source; 
 an optical splitter coupled to the second EO modulator and providing an output to the second optical BPF; 
 a second OE detector coupled to the optical splitter; and 
 an RF BPF coupled to the second OE detector and providing a fixed local oscillator (LO) signal to the second EO modulator. 
 
     
     
       4. The communications system of  claim 1  further comprising:
 a first wavelength division multiplexing (WDM) demultiplexer coupled between the first EO modulator and the plurality of photonic mixers; and 
 a second WDM demultiplexer coupled between the optical source and the plurality of photonic mixers. 
 
     
     
       5. The communications system of  claim 4  further comprising at least one WDM combiner coupled to outputs of the plurality of photonic mixers. 
     
     
       6. The communications system of  claim 4  further comprising at least one intermediate frequency (IF) combiner coupled between the at least one first OE detector and the ADC. 
     
     
       7. The communications system of  claim 6  further comprising at least one photonic lantern coupled to outputs of the plurality of photonic mixers. 
     
     
       8. The communications system of  claim 1  further comprising:
 a first optical splitter coupled between the first EO modulator and the plurality of photonic mixers; and 
 a second optical splitter coupled between the optical source and the plurality of photonic mixers. 
 
     
     
       9. The communications system of  claim 1  wherein the optical source comprises:
 a plurality of laser sources; 
 a wavelength division multiplexing (WDM) combiner configured to combine laser light from the plurality of laser sources; 
 an optical amplifier coupled to the WDM combiner; and 
 an optical splitter having an input coupled to the optical amplifier, and a respective output coupled to the first EO modulator and to the plurality of photonic mixers. 
 
     
     
       10. The communications system of  claim 1  wherein the frequency spectrum has a range between 100 MHz and 100 GHz. 
     
     
       11. A communications system comprising:
 an optical source configured to generate an optical carrier signal; 
 a first electro-optic (EO) modulator coupled to the optical source and configured to modulate the optical carrier signal based upon a radio frequency (RF) input; 
 a first wavelength division multiplexing (WDM) demultiplexer coupled to the first EO modulator; 
 a second WDM demultiplexer coupled to the optical source; 
 a plurality of photonic mixers each associated with a different respective frequency across a frequency spectrum and coupled to the first and second WDM demultiplexers, each photonic mixer comprising
 a first path coupled to the first EO modulator and comprising a first optical bandpass filter (BPF) and an optical power meter coupled to the first optical BPF, 
 a second path coupled to the optical source and comprising an optoelectronic oscillator (OEO) and a second optical BPF coupled to the OEO, and 
 an optical coupler coupled to the first and second paths; 
 
 at least one first opto-electronic (OE) detector coupled to the plurality of photonic mixers; and 
 an analog-to-digital converter (ADC) coupled to the at least one OE detector and configured to generate a digital output signal based upon receiving an RF signal via the RF input. 
 
     
     
       12. The communications system of  claim 11  wherein the OEO further comprises:
 a second EO modulator coupled to the optical source; 
 an optical splitter coupled to the second EO modulator and providing an output to the second optical BPF; 
 a second OE detector coupled to the optical splitter; and 
 an RF BPF coupled to the second OE detector and providing a fixed local oscillator (LO) signal to the second EO modulator. 
 
     
     
       13. The communications system of  claim 11  further comprising at least one WDM combiner coupled to outputs of the plurality of photonic mixers. 
     
     
       14. The communications system of  claim 11  further comprising at least one intermediate frequency (IF) combiner coupled between the at least one first OE detector and the ADC. 
     
     
       15. The communications system of  claim 11  wherein the optical source comprises:
 a plurality of laser sources; 
 a wavelength division multiplexing (WDM) combiner configured to combine laser light from the plurality of laser sources; 
 an optical amplifier coupled to the WDM combiner; and 
 an optical splitter having an input coupled to the optical amplifier, and a respective output coupled to the first EO modulator and to the plurality of photonic mixers. 
 
     
     
       16. A communications method comprising:
 generating an optical carrier signal using an optical source; 
 modulating the optical carrier signal using a first electro-optic (EO) modulator based upon a radio frequency (RF) input; 
 processing outputs of the optical source and the first EO modulator using a plurality of photonic mixers each associated with a different respective frequency from among a plurality of different frequencies across a frequency spectrum; 
 converting outputs of the plurality of photonic mixers to an RF signal using at least one first opto-electronic (OE) detector; and 
 generating a digital output signal using a common analog-to-digital converter (ADC) coupled to the at least one OE detector based upon the plurality of different frequencies across the frequency spectrum. 
 
     
     
       17. The method of  claim 16  wherein each photonic mixer comprises:
 a first path coupled to the first EO modulator and comprising a first optical bandpass filter (BPF) and an optical power meter coupled to the first optical BPF; 
 a second path coupled to the optical source and comprising an optoelectronic oscillator (OEO) and a second optical BPF coupled to the OEO; and 
 an optical coupler coupled to the first and second paths. 
 
     
     
       18. The method of  claim 17  wherein the OEO further comprises:
 a second EO modulator coupled to the optical source; 
 an optical splitter coupled to the second EO modulator and providing an output to the second optical BPF; 
 a second OE detector coupled to the optical splitter; and 
 an RF BPF coupled to the second OE detector and providing a fixed local oscillator (LO) signal to the second EO modulator. 
 
     
     
       19. The method of  claim 16  further comprising:
 demultiplexing an output of the first EO modulator using a first wavelength division multiplexing (WDM) coupled to the plurality of photonic mixers; and 
 demultiplexing the optical source using a second WDM demultiplexer coupled to the plurality of photonic mixers. 
 
     
     
       20. The method of  claim 19  further comprising combining outputs of the plurality of photonic mixers using at least one WDM combiner. 
     
     
       21. The method of  claim 19  further comprising combining outputs of the plurality of photonic mixers using at least one intermediate frequency (IF) combiner coupled between the at least one first OE detector and the ADC. 
     
     
       22. The method of  claim 16  further comprising:
 splitting an output of the first EO modulator using a first optical splitter coupled to the plurality of photonic mixers; and 
 splitting the optical signal using a second optical splitter coupled to the plurality of photonic mixers.